The prevalence of extreme weather-related events at home and around the world spotlights the need for meaningful actions that make a big impact on reducing our carbon footprint. Increasing the health and resiliency of our forests is one way to create this kind of change, reducing the risk of catastrophic wildfire, disease and impacts of drought as the climate changes.
“Sustainable forest management aimed at providing timber, fibre, biomass, non-timber resources and other ecosystem functions and services, can lower greenhouse gas emissions and can contribute to adaptation,” according to the Intergovernmental Panel on Climate Change. Of the 22 million acres of forests in Washington, sustainable forest management and the manufacturing and transportation of wood products on 8 million acres of private forests offsets our carbon footprint by 12% annually, according to University of Washington research. Since Washington is the No. 2 producer of softwood lumber in the nation, supporting sustainable forest management means supporting rural economies, and a sustainable supply of renewable wood products, which store carbon for the lifetime of the wood.
Healthy trees and forests have traditionally been one of earth’s first lines of defense in regulating carbon emissions. “Trees are the ultimate carbon removal machine by taking carbon dioxide out of the atmosphere and converting it to cellulose, which stores carbon in wood either as a tree or tree product,” says Edie Sonne Hall, founder and principal of Three Trees Consulting. She adds that forests provide a “triple climate benefit” by removing carbon dioxide from the atmosphere through tree growth, sequestering carbon in wood and soil, and requiring relatively little energy when used relative to alternative materials.
So when it comes to mitigating the effects of climate change, preserving healthy, well-managed forests is a top priority for many. Deforestation — the clearing of forest land for other uses, like agriculture in the tropics — robs the environment of the forests needed to process and store carbon. That’s why scientists, governments, private forest landowners and builders are looking for profitable, useful ways to ensure that forest lands can continue to do what they do best: grow trees and use wood products.
“Studies have shown that the countries that have the highest demand for wood products have the most stable, or even increasing, carbon stocks,” says Sonne Hall. “And that is just the carbon in the forest. Add to that the carbon stored in long-term wood products and the relatively lower energy needed to make wood products versus other materials that provide the same function, and you have a win-win-win for climate change.”
Enter cross-laminated timber or CLT, an engineered wood product that has been a popular building material in other countries for years and is now picking up steam in Washington state and other places in the U.S. CLT is made by bonding several layers of kiln-dried lumber boards stacked in alternating directions, and then pressing them to form durable panels that are lighter than steel. These panels can then be used to build walls, floors and even roofs. What’s more, CLT panels are fire-resistant, making them safe to use in tall buildings that previously could only be built with materials like concrete and steel — materials whose production generates huge amounts of greenhouse gases.
“The biggest advantage of a CLT-based building system over its traditional counterpart is the environmental benefits,” says Indroneil Ganguly, associate professor at the University of Washington School of Environmental and Forest Sciences. “We all know about the huge environmental impact of traditional mid to high-rise building systems. CLT’s role in CO2 emissions reduction is twofold. It displaces one of the most polluting materials (cement) and keeps the atmospheric carbon sequestered within the buildings for a long period.”
Ganguly estimates that carbon sequestered in CLT products remains there for 70 to 100 years. Over that same amount of time, the land from which the wood for the CLT was originally harvested can be used to grow two more cycles of trees, offering a dramatic impact in climate change mitigation.
“In a study we conducted, we estimated that the net CO2 emission reduction in CLT hybrid buildings is approximately 27%,” says Ganguly.
The Washington Forest Protection Association, a trade association representing private forest landowners in Washington state, estimates that the total amount of carbon sequestered on private forests and in manufactured wood products like CLT offsets 12% of Washington’s carbon emissions, even after considering all emissions associated with their production.